New target methods for memory tagging support

This patch starts adding some of the generic pieces to accomodate memory
tagging.

We have three new target methods:

- supports_memory_tagging: Checks if the target supports memory tagging. This
  defaults to false for targets that don't support memory tagging.

- fetch_memtags: Fetches the allocation tags associated with a particular
  memory range [address, address + length).

  The default is to return 0 without returning any tags. This should only
  be called if memory tagging is supported.

- store_memtags: Stores a set of allocation tags for a particular memory
  range [address, address + length).

  The default is to return 0. This should only
  be called if memory tagging is supported.

gdb/ChangeLog:

2021-03-24  Luis Machado  <luis.machado@linaro.org>

	* remote.c (remote_target) <supports_memory_tagging>: New method
	override.
	<fetch_memtags>: New method override.
	<store_memtags>: New method override.
	(remote_target::supports_memory_tagging): New method.
	(remote_target::fetch_memtags): New method.
	(remote_target::store_memtags): New method.
	* target-delegates.c: Regenerate.
	* target.h (struct target_ops) <supports_memory_tagging>: New virtual
	method.
	<fetch_memtags>: New virtual method.
	<store_memtags>: New virtual method.
	(target_supports_memory_tagging): Define.
	(target_fetch_memtags): Define.
	(target_store_memtags): Define.
	* target-debug.h (target_debug_print_size_t)
	(target_debug_print_const_gdb_byte_vector_r)
	(target_debug_print_gdb_byte_vector_r): New functions.

1 files changed, 24 insertions, 0 deletions

diff --git a/gdb/target-debug.h b/gdb/target-debug.h
index 1cc8256..c3004c2 100644
--- a/gdb/target-debug.h
+++ b/gdb/target-debug.h
@@ -212,4 +212,28 @@ target_debug_print_signals (gdb::array_view<const unsigned char> sigs)
   fputs_unfiltered (" }", gdb_stdlog);
 }
 
+static void
+target_debug_print_size_t (size_t size)
+{
+  fprintf_unfiltered (gdb_stdlog, "%s", pulongest (size));
+}
+
+static void
+target_debug_print_const_gdb_byte_vector_r (const gdb::byte_vector &vector)
+{
+  fputs_unfiltered ("{", gdb_stdlog);
+
+  for (size_t i = 0; i < vector.size (); i++)
+    {
+      fprintf_unfiltered (gdb_stdlog, " %s",
+			  phex_nz (vector[i], 1));
+    }
+  fputs_unfiltered (" }", gdb_stdlog);
+}
+
+static void
+target_debug_print_gdb_byte_vector_r (gdb::byte_vector &vector)
+{
+  target_debug_print_const_gdb_byte_vector_r (vector);
+}
 #endif /* TARGET_DEBUG_H */